Roof Framing Plan Roofing C Purlins

Roofing terms when framing a roof figure 7 2 carpenters must be familiar with commonly used roofing terms figures 7 3 and 7 4.

Roof framing plan roofing c purlins.

The purlins support the long span steel roofing but before the roof itself is put on a metal facia frame is installed around the perimeter of the roof. C section purlins or cee section purlins are designed to form the walls and floor joists of a building shell structure making them also ideal for supporting beams needed for mezzanine flooring. Rafters rafters make up the main framework of all roofs. The shape of cee purlins does not allow end lapping they are butted together.

This frame supports and is hidden by a metal facia board. In the past the majority of roof structures were of wooden construction but over the past 15 to 20 years there has been a vast shift away from wood to metal mainly steel roof construction. Metal c purlins are light in weight and perfect for simple span construction. They vary in size depending on length and spacing.

The steel purlins are in turn supported by rafters or walls. Cee purlins are secondary steel framing members most commonly used as roof purlins wall girts and header jamb and sill for windows and doors on metal buildings. A common arrangement is a rafter and purlin system which combines purlins and rafters. The facia frame may also supports the soffit.

The tops of inclined rafters are fastened to. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. Also referred to as secondary structurals this type of framing runs in between primary framing elements creating a structure within a structure much like cross beams in a wooden building. They are inclined members spaced from 16 to 48 inches apart.

Secondary framing is an important component of many pre engineered metal buildings. Our frame is welded up of 1 x 1 angle bar and 1 flat bar. In addition our c section purlins can also be used for door framing roof trimming window trimming parapet rails and side rails also see z purlins. Purlins traditionally support the roof deck cladding sheeting and are in turn supported by the principal rafters steel beams etc.

In steel construction the term purlin typically refers to roof framing members that span parallel to the building eave and support the roof decking or sheeting.